Interactions in Intersecting Brane Models

TL;DR

This paper calculates scattering amplitudes in type II string models with intersecting D-branes, revealing contact interactions and their interpretation as exchanges of various string excitations, relevant for flavor physics.

Contribution

It provides explicit calculations of four-fermion amplitudes in intersecting brane models and interprets these in the field theory limit, highlighting new contact interactions.

Findings

Contact interactions can induce flavor-changing effects.

Amplitudes interpreted as exchanges of Kaluza-Klein and string oscillator states.

Explicit four-fermion amplitude calculations in intersecting brane setups.

Abstract

We discuss tree level three and four point scattering amplitudes in type II string models with matter fields localized at the intersections of D-brane wrapping cycles. Using conformal field theory techniques we calculate the four fermion amplitudes. These give "contact" interactions that can lead to flavour changing effects. We show how in the field theory limit the amplitudes can be interpreted as the exchange of Kaluza-Klein excitations, string oscillator states and stretched heavy string modes.